When most people go through a traumatic romantic experience, they receive nothing but sympathy. When it happens to an artist, their dealer’s condolences may be suspiciously forced. As Philip Hook, a director at Sotheby’s, explained at the Hay Festival, the reason is simple. We may think artists are judged on the quality of their work. But as the million-pound price tag for Tracey Emin’s unmade bed suggests, the market does not work like that. Lunacy, rebellion, dying young, any kind of “positive romantic baggage” – such qualities send prices soaring (with the exception of nude works, which apparently fall foul of the Middle Eastern buyers who dominate the market). Which leads to the depressing prospect of van Gogh’s successors lopping off their ears not in fits of passion, or drunkenness, or even by accident, but simply to pump up their selling price.